This multicenter randomized trial is designed to evaluate the ability of low dose insulin therapy, in association with periodic continuous insulin infusions ('beta cell rest') to delay and/or prevent the development of insulin dependent diabetes in first degree relatives of individuals with IDDM. Nondiabetic, islet cell antibody positive individuals who also have alterations in first phase insulin secretion are qualified for randomization. During the previous year, approximately 100 IDDM families who had participated in previous studies of the genetics of diabetes were contacted and informed about the DPT-1 trial. Antibody screening of some interested family members was performed but no ICA+ individuals were identified. Recruitment will continue in the coming year.